1. FIELD OF THE INVENTION
The present invention relates to a powered machine for automatically removing screw-on lids from jars.
2. DESCRIPTION OF THE PRIOR ART
Jars are commonly employed to contain household materials, particularly foodstuffs, for convenient storage and retrieval. Jars are usually equipped with thin, metallic lids, which attach to the jars by cooperating threads. For many reasons, a lid can be so tightly fitted to its associated jar that removing the same becomes a difficult task for a person attempting to open the jar. For example, a lid may be very tightly installed in the manufacturing process. Also, entrapment of fluent contents on the threads may cause the lid to stick in its tightened position. Corrosion of the lid may also cause sticking.
Even in those cases wherein the effort of unscrewing a lid is within generally accepted limits, some people are not strong enough to accomplish this task. Examples include the very young, persons with arthritis, the elderly, and those with injury to a hand or arm.
To assist persons who for whatever reason need such assistance in opening a jar, machines for unscrewing lids from jars have been proposed in the prior art. As these machines are typically intended for tabletop use, they frequently include a base having a vertical shaft on which is mounted a gripping device for holding a jar by its lid. The gripping device is disposed above a second gripping device located on the base, with the jar sandwiched between opposing gripping devices.
One of the top or bottom gripping devices is provided with rotation means, the other gripping device being immobile, so that a torque is imparted to the jar. This torque is intended to break a seal, or initial resistance, securing the lid to the jar.
U.S. Pat. No. 4,171,650, issued to John Cardinal on Oct. 23, 1979, discloses a jar lid removing machine wherein operation automatically draws opposing gripping devices toward one another by raising the jar on a movable table. The table has a member threaded to a rotatable screw. As the screw turns, the table rises in response thereto. Excessive clamping force is avoided by a torque clutch disposed in line between the screw and its associated drive motor.
U.S. Pat. No. 3,812,742, issued to Emil Polasek on May 28, 1974, discloses another motorized jar opener which holds the jar between a stationary lower friction gripping device and an upper, rotatable gripping device. The upper gripping device is motorized. A pair of lever arms adjustably hold the jar from the sides. A manually operated arm bears down on the upper gripping device, thus assuring that the lid does not slip relative to the upper gripping device.
U.S. Pat. Nos. 3,795,158, issued to Robert Y. Morita on Mar. 5, 1974, and 3,950,801, issued to Howard J. Morrison on Apr. 20, 1976, disclose typical jar lid removing machines. Each of these two inventions provides a manually operated, vertical locking device holding the jar clamped between upper and lower gripping devices.
A hand held accessory for gripping a jar lid is seen in U.S. Pat. No. 4,766,781, issued to Frederick G. J. Grise et al. on Aug. 30, 1988. This device does not support and hold a jar unassisted, and is not powered.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.